Bendable thread-severing device



March 14, 1967 R. w. WINBERG 3,308,779

BENDABLE THREAD-SEVERING DEVICE,

Filed Jan. 11, 1965 INVENTOR. Ame/V4 l0. M/VGEPG mwmn;

United States Patent 3,308,779 BENDABLE THREAD-SEVERING DEVIQE Ragnar W. Winberg, 115 W. Elder Ave., Floral Park, N.Y. 11001 Filed Jan. 11, 1965, Ser. No. 424,628 3 Claims. (Cl. 112-252) The present invention relates generally to auxiliary equipment for sewing machines, and more particularly to a device for severing the sewing thread of a sewing machine preparatory to the removal of work being sewn in said sewing machine.

Usually provided as auxiliary equipment in an automated sewing machine setup is a needle positioner which at the end of a typical sewing interval is effective to move the needle into a clearance position so that the needle does not interfere with or prevent removal of the work from the sewing machine. Also preparatory to work removal, the sewing thread must be severed from said work which is easily accomplished manually, but which is best achieved mechanically as part of the functioning of the automated set-up for the sewing machine. Known thread-severing devices employ a cutting edge of some sort to achieve thread cutoff, and although said devices are generally effective they require some improvements. For example, the cutting edge of such devices must be maintained sharp for proper functioning, and this in turn requires additional adequate shielding for said edge for obvious safety reasons, all of which tends to complicate the structure of said devices. Additionally, the manner in which said devices function to achieve thread cut-off, as for example when operating like a scissors which requires cutting or shearing edges closing about the thread, renders said devices unnecessarily complex in operation and subject to malfunctioning.

Broadly, it is an object of the present invention to provide a sewing machine thread-severing device overcoming these and other prior art shortcomings. Specifically, it is an object of the present invention to provide an electrically operated thread-severing device which employs a burning member to burn through the thread when brought in contact against said thread.

Another object of the present invention is to provide an electrically operated thread-severing device which is easily coordinated with the operation of the sewing machine to sever or disconnect said thread in timed relation to the end of a stitching interval.

In achieving the foregoing object of providing electrically operated thread-severing device which on physical contact is effective to burn through said sewing thread, it is a still further object to construct said device simply and in such a manner as to readily permit adjustments to be made in the position of the burning member of said device to assure physical contact with said thread and thus the proper functioning of said device.

A thread-severing device demonstrating features of the present invention broadly includes mechanical elements and appropriate electrical circuitry for employing the flow of electric curent to heat up a burning member forming an integral part of said device and which member, at a point of physical contact against said thread, is effective to sever or disconnect said thread. Specifically, said mechanical elements include a tubular housing for the electrical wiring to said burning member, said burning member more particularly being mounted in an exposed position in an end of said tubular housing. A noteworthy feature of construction of said housing is that at the end thereof mounting the burning member said housing is readily bendable to achieve a position for said burning member which assures subsequent physical contact of this member against the sewing thread. Appropriate means additionally are employed to pivotally mount the housing on the sewing machine so that the burning member is selectively movable from a clearance position removed from the work-stitching location of the sewing machine into an operative position in proximate relation thereto, in which operative position said burning member makes physical contact with and is effective to burn through said thread and thereby disconnect said thread from work being sewn in said sewing machine at said work-stitching location.

The foregoing brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front elevational view of a sewing machine with an attached thread-severing device demonstrating features of the present invention;

FIG. 2 is a fragmentary plan view projected from FIG. 1 and better illustrating the manner in which said threadsevering device is mounted on said sewing machine;

FIG. 3 is a fragmentary rear elevational view, with portions thereof broken away, of the mechanisms causing movement of said thread-severing device; and

FIG. 4 is a schematic representation of the electrical circuit for said thread-severing device.

Shown in the drawings is a thread-serving device, generally designated 10, attached to and functioning as auxiliary equipment for a conventional sewing machine 12. Whereas the majority of thread-severing device attachments for sewing machines employ a cutting edge of some sort to sever the sewing thread from work in said sewing machines, the thread-severing device 10 of the present invention will be understood to be an electrically energized device employing heat produced by an electric current flow to burn through said thread at a point of contact with said thread at which it is desired to sever said thread. The sewing machine may be any conventional type having a vertical reciprocating sewing action, or it may be a blind stitch type of sewing machine such as the illustrated machine 12 which has a needle 14 mounted on an arm 16 which is laterally rotated into and out of sewing engagement with a fabric 18 which it is desired to blind stitch. Machine 12 include a main body 20 and a lengthwise journalled drive shaft 22 therein which has an end pulley 24 and a conventional pulley belt 26 trained about said pulley 24 and at its other end driven by the sewing machine motor (not shown). At the other end of the sewing machine main body 20 is a sewing head 28 housing the usual sewing mechanisms including a shaft 30 extending from said head and on which said arm 16 is approximately mounted. Supported on a lateral extension 32 beneath the sewing head 28 is the conventional sewing machine work or fabric holding and feeding mechanisms, herein generally and collectively designated 34. As is generally understood, the machine 12 operates in a well known manner to apply blind stitching to fabric workin-process 18 in a thread-stitching location, herein designated 38, within the holding and feeding mechanisms 34, said stitching being more particularly applied by the laterally reciprocating needle 14 threaded with sewing thread 40 and effective to produce stitching in said fabric work 18. As is also generally understood, usually included as conventional auxiliary equipment for an automated set-up for said sewing machine 12 is a needle positioner (not shown) which at the end of a typical sewing interval is effective to move the needle 14 to the clearance position relative to the fabric 18 as is depicted in FIG. 1. If an automatic needle positioner is not available, the needle clearance position may be achieved by the sewing operator manually rotating the driving shaft 22 at the pulley end of said shaft. This clearance position of the needle 14 in which said needle 14 is removed from the work 18 is required preparatory to removal of said work from the machine 12. At this time, it is also desirable to operate the thread-severing device It to sever the sewing thread 49 at some point along the length portion 40a thereof between engagement of said thread with the work 18 and with the sewing needle 14.

As can be best appreciated by a comparison between FIGS. 1-3 illustrating the mechanical features of said thread-severing device and FIG. 4 illustrating the elec trical circuitry thereof, the device 10 includes conventional electrical wiring 42 in a main electrical circuit 43 and having an exposed burning member, preferably in the form of a heating coil 44, connected in said main circuit 43, and an associated energizing circuit 46 which, as is subsequently described herein, is effective to produce an adequate electric current How in said main circuit 43 to heat up the coil 44 to a temperature sufiicient to burn through the sewing thread 40 when said coil 44 is brought into physical contact against said thread 40. As is best shown in FIGS. 1, 2 the electrical wiring 42 directly connected to the coil 44 is conveniently housed in a conventional tubing 48, which will be understood to be fabri cated of readily bendable material such as copper or the like, and which housing is bent along a length portion 48a as at one end thereof and retains this bent shape until the same is physically changed or modified. The base of the burning member or coil 44 is retained in an insulated mounting member 50 in said bent end of said tubular housing 48 and simply by providing a proper curvature or other suitable shape to said housing bent portion 48a the position of the exposed coil 44 relative to the sewing thread 40 can be so oriented as to assure physical contact therebetween in the operative position of said coil 44. More particularly, by trial and error it is contemplated that a clearance position for said coil 44 as depicted in full line in FIG. 1 will be provided that in turn will provide the necessary physical contact of said coil 44 against the thread 40 when the coil 44 is subsequently pivoted into an operative position in proximate relation to said thread 40 as depicted in phantom perspective in FIG. 1.

As best shown in FIG. 2, pivotally mounting the tubular housing 48 is a bracket 52 bolted as at 54 onto the top fiat surface of the sewing head 28 and having upright ears 56, 58 at opposite ends receiving the ends of said tubular housing 48 therethrough. Fixedly mounted on the remote end of the tubular housing 48 is a lateral actuating arm 60 operatively connected via a link 62 to a plunger 64 of a conventional solenoid 66. As is generally understood, the operation of the solenoid 66 is such that when electrically energized the plunger 64 is withdrawn within the body of said solenoid 66 and is effective to pivot the housing 48 about the longitudinal axis of said housing, thereby resulting in movement of the coil 44 from its clearance position into its operative position. To limit or otherwise adjust the extent of this pivotal movement, a cross-piece 68 is approximately secured medially of the housing 48 and has a threadably adjustable stop 70 in each of its opposite ends.

Referring now specifically to FIGS. 3 and 4, it will be seen that mounted on the rear of the sewing head 28 is a box 69 housing the solenoid 66 and having an opening 71 therein for the plunger link 62. Also conveniently housed within the box 69 is a conventional transformer 72 and a variable resistor 74, both of which form part of the electrical circuitry for the thread-severing device 10. More particularly, the energizing circuit 46 as clearly shown in FIG. 4 has contacts 76 for making connection to a conventional 110 volt electrical power source and has the primary winding 72a of said transformer 72 connected therein While the secondary winding 72b of said transformer is connected in said main circuit 43 to step down the voltage in said main circuit 72 to a recommended 6 volts as an anti-shock precaution. The rheostat or variable resistor 74 is connected in the main circuit 43 and provides, through positioning of the slider '74:: thereof along the resistor wire 74b thereof, a control for adjusting current flow through the main circuit 43 and thus control over the temperature that is attained by the coil 44 to assure that said temperature is at a sutficiently high level to burn through the sewing thread 40.

The winding for the solenoid 66, designated 66a in FIG. 4, is incorporated in a separate auxiliary circuit 78 which also has connected therein one set of contacts 8% of a double-pole manually operated switch 32. The other set of contacts for the switch 82 is incorporated in the energizing circuit 46. Completing the auxiliary circuit 78 is a two-position control switch 34 which will be understood to be operated in timed sequence to the operation of the sewing machine 12 and thus in accordance with sewing intervals of said sewing machine. The control switch 84 may, for example, be advantageously integrated with the operation of the usual manual knee-press control of the sewing machine wherein actuation of said knee-press by the sewing operator at the end of a sewing interval is effective to also move the control switch from its position against contact 84a into position against the other contact 8411. Or control switch 84 may be electrically actuated by being connected to a solenoid which in turn may be energized when a needle positioner has provided a needle clearance position at the end of a typical sewing interval. Assuming at the time of actuation of the control switch 84 that the double-pole switch 82 is closed, it will be appreciated that the thread-severing device It as herein described is then operable to sever or disconnect the thread 40 from the fabric work 18 and thereby permit said fabric work to be removed from the sewing machine 12. More specifically, actuation of the control switch 84 completes the auxiliary circuit 78 which is effective to energize the solenoid winding 66a and thereby result in said solenoid 66 causing pivotal movement of the thread-severing device 10 into its operative position. As previously described in detail, this movement of the thread-severing device and more particularly of the coil 44 thereof brings said heated coil 44 in contact against the sewing thread 46) and is effective to burn the thread at said point of contact. Upon the subsequent openings of the control switch 84, the coil 44 is pivoted back into its normal clearance position removed from the thread-stitch location 38 and thus does not interfere with the sewing function of the machine 12.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

What is claimed is:

1. In combination with a sewing machine having a support and thread-stitching mechanisms at a work-stitching location of a thread-severing device for severing the the thread at said work-stitching location at the end of a stitching interval, said thread-severing device including electrical wiring and an electrically energized burning member, a tubular housing disposed about said electrical wiring and having said burning member exposed beyond one end thereof, a source of electrical energy connected to said electrical Wiring for applying electrical energy to heat up said burning member, means operatively connected to and mounting said housing on said support for moving said exposed burning member from a clearance position removed from said work-stitching location to an operative position in proximate relation to said workstitching location, and means operable in timed relation to the end of said stitching interval for moving said burning member from said clearance position to said operative position, said housing at said one end being fabricated of bendable material and being adapted to be bent to position said burning member relative to the thread at said Work-stitching location such that contact is made therebetween upon movement of said burning member into said operative position.

2. In combination with a sewing machine having a support and thread-stitching mechanisms at a work-stitching location of a thread-severing device for severing the thread at said work-stitching location at the end of a stitching interval, said thread-severing device including an electrically energized burning member, a source of electrical energy, means including electrical wiring and an adjustable resistance connecting said source to said burning member for applying electrical energy thereto to heat up said burning member, a tubular housing disposed about said electrical wiring and having said burning member exposed beyond one end thereof, means operatively connected to and mounting said housing on said support for moving said exposed burning meter from a clearance position removed from said work-stitching location to an operative position in proximate relation to said workstitching location, and means operable in timed relation to the end of said stitching interval for moving said burning member from said clearance position to said operative position, said tubular housing at said one end being fabricated of bendable material and being adapted to be bent to position said burning member relative to the thread at said work-stitching location such that contact is made therebetween upon movement of said burning member into said operative position.

3. A thread-severing device in combination with a sewing machine for severing the sewing thread of said sewing machine from work in said sewing machine comprising a source of electric current, electrical means including a burning coil connected to said electric current source and adapted in response to the flow of electric current therethrough to cause heating of said coil to a an elevated temperature sufiicient for severing said sewing thread on contact of said coil against said sewing thread, a tubular housing for said electrical means disposed thereon such that said coil is exposed beyond one end thereof and means mounting said housing on said sewing machine for selectively moving said exposed coil from a position of clearance relative to said sewing thread into an operative position in proximate relation to said sewing thread for bringing said coil into contact against said sewing thread, said housing for a portion of length at said one end being fabricated of readily bendable material and being adapted to be bent into a shape posi tioning said exposed coil relative to said sewing thread such that contact is made therebetween upon movement of said coil into said operative position.

References Cited by the Examiner UNITED STATES PATENTS 3,098,437 11/1961 Herr 112-252 2 3,188,992 6/1965 Freeman et al. 112252 5 3,191,562 6/1965 Frankel 112252 3,250,237 5/1966 Myska 112252 3,252,438 5/1966 Firestein et al. 112-252 JORDAN FRANKLIN, Primary Examiner.

PATRICK D. LAWSON, J. R. BOLER,

Assistant Examiners. 

1. IN COMBINATION WITH A SEWING MACHINE HAVING A SUPPORT AND THREAD-STITCHING MECHANISMS AT A WORK-STITCHING LOCATION OF A THREAD-SEVERING DEVICE FOR SEVERING THE THE THREAD AT SAID WORK-STITCHING LOCATION AT THE END OF A STITCHING INTERVAL, SAID THREAD-SEVERING DEVICE INCLUDING ELECTRICAL WIRING AND AN ELECTRICALLY ENERGIZED BURNING MEMBER, A TUBULAR HOUSING DISPOSED ABOUT SAID ELECTRICAL WIRING AND HAVING SAID BURNING MEMBER EXPOSED BEYOND ONE END THEREOF, A SOURCE OF ELECTRICAL ENERGY CONNECTED TO SAID ELECTRICAL WIRING FOR APPLYING ELECTRICAL ENERGY TO HEAT UP SAID BURNING MEMBER, MEANS OPERATIVELY CONNECTED TO AND MOUNTING SAID HOUSING ON SAID SUPPORT FOR MOVING SAID EXPOSED BURNING MEMBER FROM A CLEARANCE POSITION REMOVED FROM SAID WORK-STITCHING LOCATION TO AN OPERATIVE POSITION IN PROXIMATE RELATION TO SAID WORKSTITCHING LOCATION, AND MEANS OPERABLE IN TIMED RELATION TO THE END OF SAID STITCHING INTERVAL FOR MOVING SAID BURNING MEMBER FROM SAID CLEARANCE POSITION TO SAID OPERATIVE POSITION, SAID HOUSING AT SAID ONE END BEING FABRICATED OF BENDABLE MATERIAL AND BEING ADAPTED TO BE BENT TO POSITION SAID BURNING MEMBER RELATIVE TO THE THREAD AT SAID WORK-STITCHING LOCATION SUCH THAT CONTACT IS MADE THEREBETWEEN UPON MOVEMENT OF SAID BURNING MEMBER INTO SAID OPERATIVE POSITION. 